<p>In order to predict the loss and the damage from the hazards such as debris flow resulted from dam failures, three important factors must be taken into account; the strength of hazard, the inventory and the vulnerability of the inventory to the hazard. In the case of the debris flow, the flow speed, the inundation boundary and depth, and the flow force can be the hazard. The inventory corresponds to the list of assets and demographic distribution while the vulnerability is the probability of the damage of each inventory by the specified hazard. In this study, the hazard is assessed from 3D numerical simulation of the debris flow incurred by the dam failure. Since the detail description and modeling of the inventory is nearly impossible, the present study utilized GIS-based regional assessment of the vulnerability combined with the inventory, in which the distribution of the inventory represents the exposure and the performance of the inventory such as age of building represents the sensitivity. As an example, building vulnerability index is measured by combining weighted five proxy variables; density of hazard exposed area of building, building importance level, type of building structural material, status of building structural design, and deterioration level of building. The selected proxy variables are evaluated with predefined scoring criteria and nondimensionalized based on a standardization method. The resulting vulnerability is normalized for the relative assessment with the region of interests. The computed strength of the hazard is then convoluted with the normalized vulnerability and the results show the risk of the region. This research was supported by a grant (2018-MOIS31-009) from Fundamental Technology Development Program for Extreme Disaster Response funded by Korean Ministry of Interior and Safety(MOIS).</p>
Analysis of a debris flow after Wenchuan Earthquake and discussion on preventive measures